Question

Given the equation (x + 3)2 + (y + 5)2 = 49 of a circle, identify the center and the radius

Answer 1

do u know what's the standard eq for a circle?

Answer 2

(x-h)^2+(y-k)^2=r

Answer 3

it should be r^2...not just r.
now, compare the 2 equations. what are the values of h,k and r?

Answer 4

3 5 & 49

Answer 5

don't ignore the signs.
u should get,
-h = 3
-k = 5
r^2 = 49.
got it?

Answer 6

ah ye ye i see

Answer 7

right. so now can u tell me the values h, k and r?
also, what do these variables represent in the standard eq?

Answer 8

there are multiple choices right, two of them say 7 and the other say 49

Answer 9

if r^2 = 49
then r = ?

Answer 10

it says 7 or 49. its a ll confusing

Answer 11

forget about those options. answer this:
if u've been given x^2 = 100....then can u find the value of x ?

Answer 12

yes

Answer 13

seeing its a squared value, it'll be 10, no?

Answer 14

that's right! now, a change in values.....given that r^2 = 49....what will be the value of r ?

Answer 15

wouldnt it be 7..?

Answer 16

bingo!
so u know the values of h,k,r.....just list them for me.
now, what do these variables represent, in the standard eq ?

Answer 17

(x + 3)2 + (y + 5)2 = 49

Answer 18

but its nit asking me for h,k,r.. just the C (circumfrence i guess) and r

Answer 19

no. what i'm asking is:
in the eq, (x-h)^2 + (y-k)^2 = r^2.........what do the variables h,k,r stand for?

Answer 20

trust me. to find C(that's centre, not circumference) and r, u'll need to know h,k,r.

Answer 21

mmmm thank you for helping but.. i figured it out. its the opposite of it, meaning the symbol of being positive or negative

Answer 22

that's right. (h,k) = centre and r = radius.

Answer 23

yea i see that.. thx

Answer 24

np!

Answer 25

mm since yoyr like the first person who helps me, could you help me with the rest of my questions..?